


My Good Boy

by shadowhive



Series: Diego/Klaus [7]
Category: The Umbrella Academy (TV)
Genre: Anal Fingering, Cock Rings, Face Sitting, Fisting, M/M, Praise Kink, Sibling Incest, Smut, Sub!Diego
Language: English
Status: Completed
Published: 2019-03-09
Updated: 2019-03-09
Packaged: 2019-11-14 14:53:47
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,834
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18054638
Author URL: https://archiveofourown.org/users/shadowhive/pseuds/shadowhive
Summary: Klaus wants to see just how much Diego can take.





	My Good Boy

**Author's Note:**

> I blame the Kliego discord for inspiring this, 100%! I ended up combining several things that got mentioned there so I hope you all enjoy it

Their lives had all changed since they had come back together, but Klaus would argue that Diego’s had changed the least. He still boxed from time to time, this time with Klaus cheering him on, looking completely out of place. (The others sometimes came too, but Klaus was always there, a permanent fixture at his fights.) Diego still went out during the nights to kick ass and take names (or as he would put it ‘saving lives baby’), although he told Klaus he went out less than he used to. Klaus always worried during the nights he was away, gravitating to the comforting presence of his other siblings.

Nights like this were much better, where Diego was saying in the house and they had some time to themselves.

Klaus licked his lips, staring down at Diego. He was spread out across his own bed, completely naked with his ankles and wrists secured in place with padded cuffs. He looked completely gorgeous like this, completely at his mercy.

To be honest, Klaus had never expected to have Diego like this. When he jerked off over him he’d always pictured him to be the one in charge, pushing him against walls or whatever the nearest surface happened to be. And yeah, when they started to fuck that was exactly the sort of thing that happened. He hadn’t expect Diego to ask to get fucked and then to be so receptive and eager when he was.

Klaus reached out for him, running his fingers up along Diego’s leg from just above the ankle restraint up towards his aching cock. A cock ring was wrapped tight around the base of it, strangling off his ability to cum and making him even more needy. “Look at you, all laid out for me.” Klaus whispered, running a fingertip up along his lover’s cock. “So very hard and eager.” Diego let out a low groan and a Klaus smirked. “Are you ready?”

“Yes...” Diego let out a breathy groan, eyes on Klaus the whole time.

“Yes what?” Klaus smirked, cradling his full balls in his hand before giving them a squeeze, just enough for him to feel it.

“Fuck... yeah, yes sir.” Diego nodded and Klaus grinned brightly up at him.

“And what do you say when you want me to stop?” Klaus asked, gently stroking his fingers against his soft skin. They’d been over this beforehand of course, but Klaus wanted to hear it again. Plus his choice of a safeword was just so very... Diego that it was endearing.

“Knives.” He replied, face slightly flushed and Klaus couldn’t help but smirk.

“Good boy.” He let go of Diego, reaching for the lube and popping it open. He squirted the fluid over his fingers, spreading it along them. Diego’s eyes were on him the whole time, watching with an intense lust. Fuck, he loved the way that Diego looked at him, like he was the hottest person in the world. “Gonna fill you up so good, think you can take it for me?”

“Yes sir.” Diego groaned out the word, his thighs parting a little more. “Please.” He added and Klaus loved when Diego begged like that. His big strong man begging to have his ass filled, he made him ache in all the right ways.

Klaus got onto the bed, slotting himself between Diego’s legs and he set the lube next to his chest, within easy reach. He reached down with his left hand, running it over Diego’s chest, stopping to play with his pierced nipple before moving lower. He bypassed his aching dick, using his fingers to part Diego’s ass cheeks. His hole twitched, looking like it was just begging to be filled up and Klaus was all too eager to oblige him. He bought up his middle finger, pressing the slick finger against his ring, circling it gently.

“You look so needy for me.” Klaus whispered, pushing as he slowly pushed his middle finger into him. “You need to be filled don’t you?”

“Yes sir, fuck...” Diego groaned, trying to rock back against the finger, his eyelids fluttering. “Please...”

“Please what?” Klaus asked with a smirk, crooking his finger as he sank it fully inside him. It was a move that made Diego gasp, making him stumble over his words.

“M... m... more.”

Klaus could be cruel, could make him elaborate on what he wanted more of but he decided instead to be kind. He drew his finger back, loving the whimper that left Diego’s lips. “More is coming, don’t worry.”

He pressed his ring finger alongside his middle one, gently pushing both into him. Diego always took them so well, he was impressed. Klaus kept his gaze on Diego’s opening, watching as it twitched around the fingers inside him. “You look beautiful like this.” Klaus murmured as he worked his fingers in and out, spreading them slightly once they were in him fully. “Gonna open you up more than you ever have before.”

Diego groaned at his words and Klaus was sure he could see his cock ached. He was tempted to touch it again but he didn’t want to overstimulate him, not yet anyway. His fingers worked on opening him him up further, spreading a little wider each time they sank into Diego’s tight heat. “You love it don’t you? Love having my fingers deep inside you?”

“Y... Yes s... sir...” Diego gasped, trying to push back against him and Klaus used his free hand to press his thigh down. “Please... more.”

Klaus couldn’t stop the grin from forming across his face, loving how desperate Diego sounded. “Well since you asked so nicely...” He drew his fingers back, pressing a third alongside the first two. Diego groaned, low and desperate as he took them all. “Yeah, you should see your hole, it looks so good being filled up.” He twisted his fingers once they were fully in him, a beautiful desperate sound leaving his lips. Diego’s cock throbbed again and Klaus wondered if he could get him off with just his fingers. Another time. “You looked so good the other night when you wore that plug, I think it should be a permanent feature don’t you?” Diego opened his mouth, no doubt to form some kind of response but Klaus just curved his fingers, brushing his tips against his spot and making him groan. “I mean, after all you have to wear that ridiculous leather outfit with a that harness, looking like someone’s wet dream come to life. May as well go the whole way huh?”

His fingers thrust into him, making any response Diego could have made die on his lips. Klaus made a mental note to get him in that outfit again, because fuck it was a great look on him. “Then again if you were kicking ass that plug might be too distracting huh? Especially if they threw you on the floor and made it shift just right.” As he spoke he continued moving his fingers in and out, parting them and stretching him even further.

“F.... fuck...” Diego was practically trembling now and Klaus had to press him down harder to hold him in place. His neglected cock looked so needy that Klaus almost felt sorry for him, almost reached down and took him in his mouth to give him some for of relief.

“Maybe we should pay another visit to the sex store. I’m sure I could find a few other things to go with your outfit.” Diego’s eyelids fluttered, his lips parted to gasp. “I mean why stop at just a plug right? We could get you a bondage harness or a cock cage to go with the plug. It would be such a good look for you I think...”

“Sir...” The word came out from Diego’s, somehow managing to sound even more desperate.

Klaus smirked, his eyes darting back down to his hole which was stretched even more than it had ever been. “You’re doing so good, taking this so well.” Klaus stroked his fingers along his thigh, loving that he was the one taking him apart like this. “Think you can take more?”

“Y... yeah...” Diego nodded, his voice sounding strained. Klaus had a feeling if it wasn’t for the ring around him his stomach would be sticky with more than just a sheen of sweat.

“Good boy.” Klaus leaned down over him, giving him a quick and gentle kiss. It was just enough to show just how much he meant the words, how proud he was of him for doing so well. Diego leaned into the kiss, letting out a low whine when Klaus pulled back. “Shhh baby boy, you know I can’t fill you just right and kiss you at the same time.” Diego nodded and Klaus smiled, moving back as he drew his fingers out again, until just the fingertips were inside him. He pressed his pinky and thumb against the rest, then looked up at Diego. “Ready?”

“Y... yeah, please....” Klaus smiled and he wished he could kiss him again. Instead, he gave him what he wanted, easing his fingers back inside him, loving the gasp he made at the addition of the extra digits. It didn’t take much effort for him to slide the rest of his hand inside and Klaus marvelled as it disappeared into him. He always marvelled at how much another Pperson could take and seeing his inked palm slide into Diego was just one of the hottest things he’d ever seen. 

“Look at you, taking my hand so well.” He whispered the praise, slightly awed by the sight of him. He reached for the lube, popping it open and drizzling some more across his palm. “You’re doing so well for me.” Diego’s head was tipped back, looking blissed out. 

“C... can...”

“Breathe. Focus on your words.” Klaus smiled at him, keeping his hand still. It was adorable to hear Diego stuttering in situations like this. He heard Diego take a breath, his body trembling slightly. “Now, what do you want?”

“Can I...” He took another breath, turning his head to meet Klaus’ eyes. “Can I see?”

“That’s it, good boy. Of course you can.” Klaus smiled and nodded, proud of him again. He reached over to his bedside table, grabbing the hand mirror from it and moving it between his legs. He angled it so that he could see the reflection from his position. “See? Look how full you are.”

“Fuck....” Diego whispered the word out, his eyes wide at the sight. Klaus couldn’t help but smirk, flexing his fingers in his tight heat, making him groan.

“You look so good like this, so full. My good boy.” Klaus smiled, setting the mirror to one side and circling his wrist against Diego’s hole. Klaus could see how much he was aching and he could tell from Diego’s expression that he’d want to do this again. “I’m so proud of you.” Diego smiled at him, big and wide, looking like a cross between blissed out and grateful. “I bet you want to cum don’t you huh?”

Diego nodded, gasping as Klaus flexed his fingers again. He decided to still his movements to give him chance to respond verbally. It took a few moments and a few shuddering intakes of breath but he eventually found the words. “If... if you’ll let me s... sir.”

Klaus couldn’t hold back his grin at that, twisting his hand inside him as a reward. “Oh I’m so lucky to have such a good boy.”Another twist, this time with more wiggling of his fingers. “Such an obedient boy.”

“Th... thank you s... sir.” He was groaning from every slight movement Klaus made and he couldn’t help smirking at the sounds. Fuck Klaus was so hard too, his cock aching in his panties from every noise he made.

“How about this.” Klaus hummed, continuing to move his hand but at a more lazy pace so that Diego could focus on his words. “I stroke your cock once you’ve got me off.”

“Ye.... yes sir... what do you... want...” He smiled, it was endearing really, but he figured he’d speed things along.

“I want to sit on your face. I want you to use that talented tongue of yours to get me off.” Diego’s eyelids fluttered and he gasped. “You think you can do that for me?”

“Y... yes. Yes sir.” Diego nodded, with a gasp and Klaus smiled, easing his hand out of him. Klaus smiled at how slick it looked, the lube glistening in the light. Diego whimpered when his fingers were removed from his hole and he just looked so empty without them.

“Would you like me to fill you with the dildo?” Klaus asked, marvelling again at the way his stretched out pucker twitched, seemingly needy for it.

“P... please.”

Klaus smiled, giving Diego another quick kiss before pulling open the drawer to his beside table. Within were the few things he’d purchased from the sex store, bar the ones he was using of course. The dildo was a simple thing, fairly small and black. It wouldn’t fill Diego even half as well as his hand, but then he had never expected Diego to actually ask for this so soon. Another reason why he was so proud of him. 

Klaus pressed the rubber shaft into him, the lube from his hand enough to make it sink home easily. Klaus wouldn’t be surprised if it slipped out for how much he had stretched him, but it wouldn’t matter. “Such a good boy. Are you ready?” Diego nodded and Klaus decided that was enough. He hooked his fingers in his lace panties, pushing the fabric down to the floor and stepping out of them.

Klaus mounted the bed, easily slotting his legs either side of his lover’s body. He settled down on him, his ass settling on Diego’s face and he closed his eyes. “Mmm be a good boy n... fuck...”

Diego’s breath was hot against his skin as his talented tongue snaked out, licking along his cleft and circling his hole. As far as he knew this was the first time Diego had done this, but like so many things they had done, he was a natural. The soft muscle pressed into him, wiggling and licking against him in all the right ways.

Klaus let out a gasp, his eyelids fluttering at the feeling. He was sure that Diego could get him off with just his tongue alone, but he decided he should help speed things along. He wrapped his lube slick hand around his dick, stroking himself steadily. “Oh yeah, just like that. You’re doing such a good job, fuck...” He groaned softly, his words of praise becoming more breathless as Diego’s tongue delved inside him as deeply as he could. “I’m so lucky to have someone as good as you, to have your talented tongue working me like this.” His free hand reached down, pinching Diego’s unpierced nipple. The action made Diego’s dick twitch pleasingly between his legs. Fuck, he looked like he could blow from the slightest touch.

Klaus stroked himself as quickly and eagerly as he could, desperate not just to get himself off but to see his lover cum too. “You look amazing like this.” He found himself rambling, breathless. “Bound and spread out and mine. Shit...” His tongue just did this fluttering thing and it made his cock ache in his hand. “That’s it, so close... fuck...” Diego did it again and he opened his eyes, angling his cock towards Diego’s aching dick, spilling hot and thick over the aching shaft. 

He couldn’t move his fingers fast enough, removing the ring from Diego and stroking his cum slick shaft. “Such a good boy. So good for me. Cum for me now beautiful, you’ve done so well.” Diego groaned, the sound muffled by the curve of Klaus’ ass. His hips ached up from the bed, as much as his restraints would allow, and he came all over them both. It was such a beautiful sight, one that would be engrained in his mind forever. “That’s it, so good.” He bought his fingers, covered in a mix of their cum, up to his lips and he licked them clean. “We taste so good.” He purred with a breathless smile on his lips, moving to sit on the bed beside him.

His fingers worked to undo the restraints that had held his lover in place. “Did you like it?” He asked as he rubbed at his wrists gently. Diego smiled and nodded at him, apparently too breathless to reply. Instead he just gave him a thumbs up, which was good enough for him. Grinning, Klaus laid down beside him, wrapping his arms around him and holding his lover close to him. “You did so good. So very good.” 

Diego smiled at him, kissing him gently and nuzzling up against him. Klaus let his eyelids flutter closed, completely content and spent.

**Author's Note:**

> As always, comments are amazing!


End file.
